It's also a signal that the House won't take action -- though nothing has been decided for certain, since leaders there have said all along they are waiting for the Senate.

"Absent a stunning turn of events, we're not going to do tax cuts before the election," the aide told TPM.

The aide said it's already a winning message without a vote since Obama and Democrats have framed the debate as the Republicans being for the rich and Democrats wanting to help the middle class. Others have made similar arguments, but several lawmakers have said they think a vote is the only way to score a political victory. The senior aide doesn't think so.

"We have a winning message now, why muddy it up with a failed vote, because, of course, Republicans are going to block everything," the aide said.

Another Democratic Senate source hesitant to even discuss the inner-workings of the caucus said it's the senators who are facing tough reelection bids this fall who have been driving the discussions. Senators are huddling today for a caucus, but multiple sources we spoke with believe the vote is scrapped.

Aides for two senators in tough bids have suggested they would take the plunge and vote before the election, but they'd prefer to vote if it means the tax cuts extension could actually be passed. And that's not counting the conservative Democrats who disagree with the majority of the caucus about where the threshold should be -- and lean toward a higher than $250,000 in income definition of the middle class.

Sen. Russ Feingold (D-WI) has told Senate Majority Leader Harry Reid he wants to vote to extend the middle class tax cuts before the elections, a Feingold aide told TPM. The senator wants to see the cuts for the wealthy expire.